Cis-substituted fluoromethylpyrrolidine derivative

ABSTRACT

An antibacterial drug having potent antibacterial activities upon various bacteria including resistant strains and high safety is disclosed, which comprises as an active ingredient, quinolone derivatives represented by the following formula (I), its salts or hydrates thereof:                    
     wherein R 1  represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, 
     R 2  represents a halogenomethoxyl group or an alkoxyl group, 
     R 3  represents an alkyl group, an alkenyl group, a halogenoalkyl group, a cyclic alkyl group, a heteroaryl group, an alkoxyl group or an alkylamino group, and 
     R 4  represents a hydrogen atom, a phenyl group, an acetoxymethyl group, a pivaloyloxymethyl group, an ethoxycarbonyl group, a choline group, a dimethylaminoethyl group, a 5-indanyl group, a phthalidinyl group, a 5-alkyl-2-oxo-1,3-dioxol-4-ylmethyl group, 3-acetoxy-2-oxobutyl group, an alkyl group, an alkoxylmethyl group or a phenylalkyl group. These substituents may further have additional substituents.

TECHNICAL FIELD

This invention relates to an8-(substituted)alkoxy-4-oxoquinoline-3-carboxylic acid derivative having3-(S)-amino-4-(S)-fluoromethylpyrrolidin-1-yl group at the 7-position ofthe quinoline nucleus as a substituent, which has excellentantibacterial activity, good pharmacokinetics and high safety, and to anantibacterial agent and an antibacterial preparation, which contain thecompound.

This invention also relates to a compound which is useful forintroducing a substituent at the 7-position that has such a structurethat excellent antibacterial activity, pharmacokinetics and safety canbe added to synthetic quinolone antibacterial agents in which thestructure of the substituent at the 7-position exerts importantinfluences upon the antibacterial activity, pharmacokinetics and safety.

BACKGROUND ART

Since the discovery of norfloxacin, antibacterial activity andpharmacokinetics of quinolone synthetic antibacterial agents have beenimproved, and many compounds are now used in the clinical field aschemotherapeutic agents which are effective in almost systemicinfectious diseases.

In recent years, generation of bacteria having low sensitivity toquinolone synthetic antibacterial agents has been increasing in thefield of clinics. For example, like the case of Staphylococcus aureus(MRSA) which is non-sensitive to β-lactam antibiotics, a case has beenincreasing in which a bacterium originally resistant to drugs other thanquinolone synthetic antibacterial agents becomes low-sensitive toquinolone synthetic antibacterial agents too. In consequence,development of a drug having further high efficacy has been called forin the field of clinics. On the other hand, it has been revealed thatquinolone synthetic antibacterial agents cause a side effect in whichsevere convulsion is induced when a non-steroidal anti-inflammatory drugis simultaneously used, as well as other side effects such asphototoxicity and the like, so that development of a quinolone syntheticantibacterial agent having higher safety has also been called for in thefield.

Quinolone-carboxylic acid derivatives which has thecis-3-amino-4-fluoromethylpyrrolidin-1-yl group related to the presentinvention as a substituent are disclosed for example in JP-A-62-19583,JP-A-63-45261 and JP-A-63-152318 (the term “JP-A” as used herein meansan “unexamined published Japanese patent application”), and thesepatents describe compounds represented by the following formula.However, though the substituent at the 7-position of these disclosedquinolones is a cis-3-amino-4-fluoromethylpyrrolidin-1-yl group, theyare compounds which have the 8-fluoroquinoline nucleus in which the8-position substituent is a halogen atom, and nothing is described abouta compound which has the 8-methoxyquinoline nucleus related to thepresent invention. In addition, there is no illustrative disclosure inthese specifications concerning an optically active compound3-(S)-amino-4-(S)-fluoromethylpyrrolidine or3-(S)-amino-4-(S)-fluoromethylpyrrolidinyl group.

(In the above formula, R⁵ is a hydrogen atom or a fluorine atom.Definition of the substituent of the compound represented by the formula(III) is unrelated to the compound of the present invention.)

In addition, JP-A-3-188074 discloses a compound represented by thefollowing formula (IV), but it does not disclose a compound which hasthe 1-cyclopropyl-8-methoxyquinoline nucleus related to the presentinvention. Also, there is no illustrative disclosure in thespecification concerning an optically active compound3-(S)-amino-4-(S)-fluoromethylpyrrolidine or3-(S)-amino-4-(S)-fluoromethylpyrrolidinyl group.

(In the above formula, R⁶ is a hydrogen atom or an amino group.Definition of the substituent of the compound represented by the formula(IV) is unrelated to the compound of the present invention.)

Also, JP-A-4-211077 discloses a compound which has the1-cyclopropyl-8-methoxyquinoline nucleus, represented by the followingformula (V). However, there is no illustration in the specificationconcerning a compound substituted with3-(S)-amino-4-(S)-fluoromethylpyrrolidinyl group.

(In the above formula, R⁷ is methyl, ethyl or the like lower alkylgroup. Definition of the substituent of the compound represented by theformula (V) is unrelated to the compound of the present invention.)

In addition, there is no description in the just described specificationabout safety of a compound represented by the following formula (VI) inwhich R⁷ is a methyl group.

DISCLOSURE OF INVENTION

The inventors of the present invention have carried out tests on thesafety of the compound represented by the formula (VI) and found as theresult that its mouse peripheral blood micronucleus test was positive(micronucleus inducing action).

The present inventors have conducted intensive studies with the aim ofproviding a compound which has excellent antibacterial activity, highefficacy and excellent safety in the clinical field. As the result, ithas been found that an 8-methoxyquinoline compound substituted with3-(S)-amino-4-(S)-fluoromethylpyrrolidin-1-yl group, represented by thefollowing formula (I), is superior to its corresponding8-methoxyquinoline compound substituted with3-(S)-amino-4-(S)-methylpyrrolidin-1-yl group, represented by theaforementioned formula (VI), thereby resulting in the accomplishment ofthe present invention.

That is, it has been found that the compound represented by thefollowing formula (I) is possessed of excellent antibacterial activityupon a broad range of Gram-negative and Gram-positive bacteria and haveexcellent safety and pharmacokinetics, such as its micronucleustest-negative property.

[In the above formula, R¹ represents a hydrogen atom or an alkyl grouphaving 1 to 6 carbon atoms, wherein the alkyl group may have one or moresubstituent(s) selected from the group consisting of a hydroxyl group, ahalogen atom, an alkylthio group having 1 to 6 carbon atoms and analkoxyl group having 1 to 6 carbon atoms,

R² represents a halogenomethoxyl group or an alkoxyl group having 1 to 6carbon atoms,

R³ represents an alkyl group having 1 to 6 carbon atoms, an alkenylgroup having 2 to 6 carbon atoms, a halogenoalkyl group having 1 to 6carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms which mayhave a substituent, a heteroaryl group which may have a substituent, analkoxyl group having 1 to 6 carbon atoms or an alkylamino group having 1to 6 carbon atoms, and

R⁴ represents a hydrogen atom, a phenyl group, an acetoxymethyl group, apivaloyloxymethyl group, an ethoxycarbonyl group, a choline group, adimethylaminoethyl group, a 5-indanyl group, a phthalidinyl group, a5-alkyl-2-oxo-1,3-dioxol-4-ylmethyl group, 3-acetoxy-2-oxobutyl group,an alkyl group having 1 to 6 carbon atoms, an alkoxylmethyl group having2 to 7 carbon atoms or a phenylalkyl group composed of an alkylene grouphaving 1 to 6 carbon atoms and a phenyl group.

In this connection, the substituent R⁴ may also be a boron-containinggroup represented by the following formula:

−B(Y¹¹)Y¹²

wherein Y¹¹ and Y¹², each independently represents a fluorine atom or analkylcarbonyloxy group having 2 to 4 carbon atoms.]

Accordingly, the present invention relates to a compound represented bythe aforementioned formula (I), its salts or hydrates thereof.

The present invention also relates to the aforementioned8-methoxyquinolone-carboxylic acid derivative, its salts or hydratesthereof in which the compound of formula (I) is a stereochemically purecompound;

the aforementioned compound, its salts or hydrates thereof, wherein R¹in the formula (I) is a hydrogen atom;

the aforementioned compound, its salts or hydrates thereof, wherein R²in the formula (I) is a methoxyl group;7-[3-(S)-amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid, its salts or hydrates thereof, wherein R³ in the formula (I) is acyclopropyl group;

the aforementioned compound, its salts or hydrates thereof, wherein R³in the formula (I) is a halogenocyclopropyl group;

the aforementioned compound, its salts or hydrates thereof, wherein R³in the formula (I) is a 1,2-cis-halogenocyclopropyl group;

the aforementioned compound, its salts or hydrates thereof, wherein R³in the formula (I) is a stereochemically pure substituent;

the aforementioned compound, its salts or hydrates thereof, wherein R³in the formula (I) is a (1R,2S)-2-halogenocyclopropyl group;

7-[3-(S)-amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-6-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid, its salts or hydrates thereof, wherein R³ in the formula (I) is a(1R,2S)-2-fluorocyclopropyl group;

a medicament which comprises the aforementioned compound, a hydratethereof, a salt of the compound or a hydrate of the salt as an activeingredient; and

an antibacterial agent or antibacterial preparation which comprises theaforementioned compound, a hydrate thereof, a salt of the compound or ahydrate of the salt as an active ingredient.

The present invention also relates to a compound represented by thefollowing formula (II), its salts or hydrates thereof:

(wherein R¹¹ and R¹² each independently represents a hydrogen atom, analkyl group having 1 to 6 carbon atoms or a protective group of theamino group,

wherein the alkyl group may have one or more substituent(s) selectedfrom the group consisting of a hydroxyl group, a halogen atom, analkylthio group having 1 to 6 carbon atoms and an alkoxyl group having 1to 6 carbon atoms, and

Q′ represents a protective group of the amino group or a hydrogen atom);and also relates to the aforementioned compound, its salts or hydratesthereof, wherein the protective group of the amino group is a protectivegroup selected from the group consisting of (substituted) alkoxycarbonylgroups, (substituted) aralkyloxycarbonyl groups, (substituted) acylgroups, (substituted) alkyl groups, (substituted) aralkyl groups and(substituted) silyl groups;

the aforementioned compound, its salts or hydrates thereof, wherein theprotective group of the amino group is a protective group selected fromthe group consisting of a tert-butoxycarbonyl group, a2,2,2-trichloroethoxycarbonyl group, a benzyloxycarbonyl group, apara-methoxybenzyloxycarbonyl group, a para-nitrobenzyloxycarbonylgroup, an acetyl group, a methoxyacetyl group, a trifluoroacetyl group,a chloroacetyl group, a pivaloyl group, a formyl group, a benzoyl group,a tert-butyl group, a benzyl group, a para-nitrobenzyl group, apara-methoxybenzyl group, a (R)-1-phenylethyl group, a (S)-1-phenylethylgroup, a triphenylmethyl group, a methoxymethyl group, atert-butoxymethyl group, a tetrahydropyranyl group, a2,2,2-trichloroethoxymethyl group, a trimethylsilyl group, anisopropyldimethylsilyl group, a tert-butyldimethylsilyl group, atribenzylsilyl group and a tert-butyldiphenylsilyl group;

the aforementioned compound, its salts or hydrates thereof, wherein oneof R¹¹ and R¹² and Q′ are protective groups of the amino group, whichare different from each other;

3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethyl-1-(R)-phenylethylpyrrolidine,its salts or hydrates thereof;

3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine, its saltsor hydrates thereof; and

the aforementioned compound, its salts or hydrates thereof, wherein oneof R¹¹ and R¹² and Q′ are protective groups of the amino group, whichare severed under different reaction conditions.

MODE FOR CARRYING OUT INVENTION

Each of the substituents of the compound of the present inventionrepresented by formula (I):

(wherein R¹, R², R³ and R⁴ are as defined in the foregoing) is describedin the following.

The substituent R¹ is a hydrogen atom or an alkyl group having 1 to 6carbon atoms, wherein the alkyl group may have one or moresubstituent(s) selected from the group consisting of a hydroxyl group, ahalogen atom, an alkylthio group having 1 to 6 carbon atoms and analkoxyl group having 1 to 6 carbon atoms.

The alkyl group may be any straight or branched group having 1 to 6carbon atoms, and its preferred examples include a methyl group, anethyl group, a normal propyl group and an isopropyl group.

When the alkyl group has a hydroxyl group as a substituent, the alkylgroup may be either straight or branched form having 1 to 6 carbonatoms, and the substituting position of hydroxyl group may preferably beon the terminal carbon atom of the alkyl group. Preferred examples ofthe alkyl group having a hydroxyl group include those which have up to 3carbon atoms, such as hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl,3-hydroxypropyl and the like groups.

When the alkyl group has a halogen atom as a substituent, the alkylgroup may be either straight or branched form having 1 to 6 carbonatoms, and a fluorine atom is desirable as the halogen atom.

When the alkyl group has an alkylthio group as a substituent, the alkylgroup may be either straight or branched form having 1 to 6 carbonatoms, and the alkylthio group may also be either straight or branchedform having 1 to 6 carbon atoms. An alkylthiomethyl group, analkylthioethyl group or an alkylthiopropyl group is desirable as thealkyl group having an alkylthio group, and the alkylthio group maypreferably have up to 3 carbon atoms. Its more preferred examplesinclude a methylthiomethyl group, an ethylthiomethyl group and amethylthioethyl group.

When the alkyl group has an alkoxyl group as a substituent, the alkylgroup may be either straight or branched form having 1 to 6 carbonatoms, and the alkoxyl group may also be either straight or branchedform having 1 to 6 carbon atoms. An alkoxymethyl group, an alkoxyethylgroup or an alkoxypropyl group is desirable as the alkyl group having analkoxyl group, and the alkoxyl group may preferably have up to 3 carbonatoms. Its more preferred examples include a methoxymethyl group, anethoxymethyl group and a methoxyethyl group.

The substituent R² is a halogenomethoxyl group or an alkoxyl grouphaving 1 to 6 carbon atoms.

As the halogen of the halogenomethoxyl group, a fluorine atom isparticularly desirable, and its number may be from 1 to 3.

The alkoxyl group may be an alkoxyl group having 1 to 6 carbon atoms,preferably a methoxyl group and an ethoxyl group.

Among these substituents, a difluoromethoxyl group and a methoxyl groupare preferred, and a methoxyl group is more preferred.

The substituent R³ is an alkyl group having 1 to 6 carbon atoms, analkenyl group having 2 to 6 carbon atoms, a halogenoalkyl group having 1to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms whichmay have a substituent, a heteroaryl group which may have a substituent,an alkoxyl group having 1 to 6 carbon atoms, an alkylamino group having1 to 6 carbon atoms or an aryl group which may have one or moresubstituent(s).

In this case, an ethyl group is desirable as the alkyl group having 1 to6 carbon atoms. A vinyl or 1-isopropenyl group is desirable as thealkenyl group having 2 to 6 carbon atoms. A 2-fluoroethyl group isdesirable as the halogenoalkyl group having 1 to 6 carbon atoms. Acyclopropyl or 2-halogenocyclopropyl group is desirable as the cyclicalkyl group having 3 to 6 carbon atoms which may have a substituent, anda fluorine atom is particularly desirable as the halogen atom of the2-halogenocyclopropyl group.

Examples of the aryl group which may have one or more substituent(s)include phenyl or the like group which may have 1 to 3 substituentsselected from the group consisting for example of fluorine, chlorine,bromine or the like halogen atom, a lower alkyl group having 1 to 6carbon atoms, a hydroxyl group, an amino group, a nitro group and alower alkoxyl group having 1 to 6 carbon atoms, and its preferredillustrative examples include a phenyl group, a 2-fluorophenyl group, a4-fluorophenyl group, a 2,4-difluorophenyl group and a2-fluoro-4-hydroxyphenyl group.

The heteroaryl group is a group derived from an aromatic heterocycliccompound which contains one or more hetero-atoms selected from anitrogen atom, an oxygen atom and a sulfur atom. Its examples includepyridyl, pyrimidyl and the like groups. As a substituent on these rings,an alkyl group, a halogen atom or the like is desirable. A methoxylgroup is desirable as the alkoxyl group having 1 to 6 carbon atoms. Amethylamino group is desirable as the alkylamino group having 1 to 6carbon atoms.

As the substituent R³, a cyclic alkyl group or a halogenocycloalkylgroup is desirable. Among these groups, a cyclopropyl group or a2-halogenocyclopropyl group is particularly desirable. A fluorine atomis desirable as the halogen atom.

Next, the halogenocyclopropyl group of R³ is described.

As the substituting halogen atom, fluorine and chlorine can beexemplified, and fluorine is particularly preferred.

Stereochemical environment at this moiety with respect to thecyclopropane ring, it is particularly desirable that the halogen atomand the pyridonecarboxylic acid moiety are located in thecis-configuration.

So-called enantiomeric isomers exist solely by thecis-2-halogenocyclopropyl moiety of R³, and strong antibacterialactivity and high safety have been observed in all of these isomers.

The present invention exerts excellent characteristics as thesubstituent represented by formula (VII):

is substituted at the 7-position of the6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid nucleus.

The present invention is characterized in that the amino group at the3-position and the fluoromethyl group at the 4-position on thepyrrolidine ring of this substituent are located in thecis-configuration and absolute configuration of (3S,4S)-form.

That is, it has been found that, when the substituent at the 7-positionof the 6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid nucleus is3-(S)-amino-4-(S)-fluoromethylpyrrolidin-1-yl group, the compound of thepresent invention shows potent antibacterial activity upon Gram-negativeand Gram-positive bacteria and also shows excellent safety and goodpharmacokinetics, such as negative property in micronucleus test,markedly weak theophylline metabolism inhibitory activity and the like.

When the compound of the formula (I) of the present invention has astructure in which diastereomers are present, and when such a compoundof the present invention is administered to human and animals, it isdesirable to administer a compound which comprises a singlediastereomer. The term “single” of “comprises a single diastereomer” asused herein means not only a case in which it is completely free fromthe other diastereomer but also a case in which it is in a chemicallypure degree. In other words, it is interpretable that the otherdiastereomer may be present in such a degree that it does not exertinfluences upon physical constants and physiological activities of thecompound.

Also, the term “stereochemically pure” as used herein means that, when acompound or the like exists in a plurality of isomer forms due to thepresence of asymmetric carbon atoms, the compound is comprised of onlyone of them. The term “pure” in this case can also be considered in thesame manner as the term “single” described above.

The 6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid derivative ofthe present invention may be used either in its free form or as an acidaddition salt or a salt of its carboxyl group. Examples of the acidaddition salt include hydrochloride, sulfate, nitrate, hydrobromide,hydroiodide, phosphate and the like inorganic acid salts, or acetate,methanesulfonate, benzenesulfonate, toluenesulfonate, citrate, maleate,fumarate, lactate and the like organic acid salts.

The salt of carboxyl group may be either inorganic or organic salt, andits illustrative examples include lithium salt, sodium salt, potassiumsalt and the like alkali metal salts, magnesium salt, calcium salt andthe like alkaline earth metal salts, ammonium salt, or triethylaminesalt, N-methylglucamine salt, tris-(hydroxylmethyl)aminomethane salt andthe like.

Also, these free form, acid addition salts and salts of carboxyl groupof the 6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid derivativemay be present as hydrates.

On the other hand, a quinolone derivative whose carboxylic acid moietyis an ester is useful as a synthesis intermediate or a prodrug. Forexample, alkyl esters, benzyl esters, alkoxyalkyl esters, phenylalkylesters and phenyl esters are useful as synthesis intermediates.

Also, the ester to be used as a prodrug is an ester which is easilycleaved after administered to form free carboxylic acid, and itsillustrative examples include acetoxymethyl ester, pivaloyloxymethylester, ethoxycarbonyl ester, choline ester, dimethylaminoethyl ester,5-indanyl ester, phthalidinyl ester, and5-alkyl-2-oxo-1,3-dioxol-4-ylmethyl ester, 3-acetoxy-2-oxobutyl eater orthe like oxoalkyl ester.

The compound of the present invention represented by the formula (I) canbe produced by various method, and, in an preferred example of thesemethods, it can be produced for example by allowing a compoundrepresented by formula (VIII):

[wherein X¹ is a substituent which serves as a leaving group, such as afluorine atom, a chlorine atom, substituted or unsubstitutedphenylsulfonyl group or a substituted or unsubstituted alkylsulfonylgroup having 1 to 3 carbon atoms, Y¹ is the R⁴ defined in the formula(I) or a boron-containing group represented by the following formula:

−B(Y¹¹)Y¹²

(wherein each of Y¹¹ and Y¹² is a fluorine atom or an alkylcarbonyloxygroup having 2 to 4 carbon atoms), and R² and R³ are as defined in theformula (I)] to react with a compound represented by formula (IX):

(wherein R¹¹ and R¹², each independently represents a hydrogen atom, analkyl group having 1 to 6 carbon atoms or a protective group of theamino group,

wherein the alkyl group may have one or more substitutent(s) selectedfrom the group consisting of a hydroxyl group, a halogen atom, analkylthio group having 1 to 6 carbon atoms and an alkoxyl group having 1to 6 carbon atoms, or an addition salt thereof (as the acid additionsalt, an inorganic acid salt or an organic acid salt can be exemplified,and its illustrative examples include hydrochloride, sulfate, nitrate,hydrobromide, hydroiodide, phosphate and the like inorganic acid salts,or methanesulfonate, benzenesulfonate, toluenesulfonate (sulfonates),acetate, citrate, maleate, fumarate, lactate (carboxylates) and the likeorganic acid salts).

The reaction can be carried out using or without using a solvent. Thesolvent to be used in the reaction may be any solvent which is inertunder the reaction conditions, and its illustrative examples includedimethyl sulfoxide, pyridine, acetonitrile, ethanol, chloroform,dimethylformamide, dimethylacetamide, N-methylpyrrolidone,tetrahydrofuran, water, 3-methoxybutanol and the like or a mixturethereof.

Preferably, the reaction may be carried out in the presence of an acidacceptor such as an inorganic base or an organic base, which includes analkali metal or alkaline earth metal carbonate or bicarbonate or thelike inorganic basic compound, or triethylamine, pyridine,1,8-diazabicycloundecene or the like organic basic compound.

The reaction temperature may be within the range of generally from roomtemperature to 200° C., preferably from approximately 25 to 150° C. Thereaction is carried out for a period of from 30 minutes to 48 hours andcompletes generally after about 30 minutes to 20 hours.

Examples of the protective group of the amino group to be used in thecompound represented by the formula (IX) include those which aregenerally used in this field, such as tert-butoxycarbonyl,2,2,2-trichloroethoxycarbonyl and the like (substituted) alkoxycarbonylgroups, benzyloxycarbonyl, para-methoxybenzyloxycarbonyl,para-nitrobenzyloxycarbonyl and the like (substituted)aralkyloxycarbonyl groups, acetyl, methoxyacetyl, trifluoroacetyl,chloroacetyl, pivaloyl, formyl, benzoyl and the like (substituted) acylgroups, tert-butyl, benzyl, para-nitrobenzyl, para-methoxybenzyl,triphenylmethyl and the like (substituted) alkyl groups or (substituted)aralkyl groups, methoxymethyl, tert-butoxymethyl, tetrahydropyranyl,2,2,2-trichloroethoxymethyl and the like ethers and trimethylsilyl,isopropyldimethylsilyl, tert-butyldimethylsilyl, tribenzylsilyl,tert-butyldiphenylsilyl and the like substituted silyl groups (the term“(substituted)” as used herein means “which may have a substituent”).

When Y¹ is an alkyl group having 1 to 6 carbon atoms, an alkoxymethylgroup having 2 to 7 carbon atoms or a phenylalkyl group composed of analkylene group having 1 to 6 carbon atoms and a phenyl group, thecompound of interest can be converted into its corresponding carboxylicacid by treating it under an acidic or basic condition which isgenerally employed for the hydrolysis of carboxylic acid esters.

When Y¹ is a boron-containing group of the formula:

−B(Y¹¹)Y¹²,

its conversion into corresponding carboxylic acid can be effected byallowing a compound represented by the formula (IX) to react with acompound of the formula (VIII) and then treating it under an acidic orbasic condition.

In addition, when deprotection is necessary, the compound of interestrepresented by the formula (I) can be obtained by removing theprotective group by selecting suitable conditions for the protectivegroup.

The compound represented by the formula (VIII) can be produced byalready known methods. Also, a compound in which Y¹ is aboron-containing group can be obtained by allowing the carboxylic acidor a ester derivative thereof to react with a boron fluoride compound oranhydrous boron carboxylate.

In the compound in which Y¹ is a boron-containing group, each of Y¹¹ andY¹² is a fluorine atom or an acyloxy group. The acyloxy group may beeither aliphatic (becomes an alkylcarbonyloxy group) or aromatic, andeither may have an additional substituent. As such a substituent, it mayhave one or more substituent(s) selected from the group consisting of ahalogen atom, an alkyl group having 1 to 6 carbon atoms and an alkoxylgroup having 1 to 6 carbon atoms. Examples of the acyloxy group includeacetyloxy, propanoyloxy, butanoyloxy, benzoyloxy, phenylacetyloxy andthe like groups, of which an acyloxy group having 2 to 4 carbon atoms(an alkylcarbonyloxy group) is preferred and an acetyloxy group isparticularly preferred.

The compound represented by the formula (IX) can be formed by removingQ′ from the compound of formula (II):

[wherein R¹¹ and R¹², each independently represents a hydrogen atom, analkyl group having 1 to 6 carbon atoms or a protective group of theamino group,

wherein the alkyl group may have one or more substituent(s) selectedfrom the group consisting of a hydroxyl group, a halogen atom, analkylthio group having 1 to 6 carbon atoms and an alkoxyl group having 1to 6 carbon atoms, and

Q′ represents a protective group of the amino group or a hydrogen atom,and

wherein the amino protective group may be a protective group selectedfrom the group consisting of (substituted) alkoxycarbonyl groups,(substituted) aralkyloxycarbonyl groups, (substituted) acyl groups,(substituted) alkyl groups, (substituted) aralkyl groups and substitutedsilyl groups.]

The compound represented by the formula (IX) and the compoundrepresented by the formula (II) can be produced by various method. Forexample, 3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidinecan be synthesized in accordance with the method described as adesirable method in Reference Examples, though not particularly limited.

The compound represented by the formula (II) can also exist in the formof a salt thereof, a hydrate thereof or a hydrate of the salt. Examplesof its acid addition salt include an inorganic acid salt or an organicacid salt, and its illustrative examples include hydrochloride, sulfate,nitrate, hydrobromide, hydroiodide, phosphate and the like inorganicacid salts, or methanesulfonate, benzenesulfonate, toluenesulfonate(sulfonates), acetate, citrate, maleate, fumarate, lactate(carboxylates) and the like organic acid salts.

When one of R¹¹ and R¹² is a protective group of the amino group and Q′is also a protective group of the amino group, these groups may be thesame or different from each other, but it is convenient to obtain acompound in which each of them is removed under different reactioncondition, namely one of them is selectively removed but the otherremains un-removed, for the production the compound (I).

The following can be exemplified as R¹¹ or R¹² (either one of them) andQ′ which are the protective groups of the amino group. That is, they are(substituted) alkoxycarbonyl groups, (substituted) aralkyloxycarbonylgroups, (substituted) acyl groups, (substituted) alkyl groups,(substituted) aralkyl groups and substituted silyl groups.

Their illustrative examples include tert-butoxycarbonyl,2,2,2-trichloroethoxycarbonyl and the like (substituted) alkoxycarbonylgroups, benzyloxycarbonyl, para-methoxybenzyloxycarbonyl,para-nitrobenzyloxycarbonyl and the like aralkyloxycarbonyl groups,acetyl, methoxyacetyl, trifluoroacetyl, chloroacetyl, pivaloyl, formyl,benzoyl and the like (substituted) acyl groups, tert-butyl, benzyl,para-nitrobenzyl, para-methoxybenzyl, triphenylmethyl and the like(substituted) alkyl groups or (substituted) aralkyl groups,methoxymethyl, tert-butoxymethyl, tetrahydropyranyl,2,2,2-trichloroethoxymethyl and the like ethers and trimethylsilyl,isopropyldimethylsilyl, tert-butyldimethylsilyl, tribenzylsilyl,tert-butyldiphenylsilyl and the like substituted silyl groups.

Cis-2-fluorocyclopropylamine comprised of a single isomer which isdesirable for the synthesis of the compound of the formula (I) comprisedof a single isomer can, for example, be synthesized by the methoddescribed in JP-A-2-231475. Synthesis of the compound of the formula (I)comprised of a single isomer can, for example, be carried out inaccordance with the method described in JP-A-2-231475, using the thusobtained optically active cis-2-fluorocyclopropylamine derivative as thematerial.

Since the compound of the present invention has potent antibacterialactivities, it can be used as medicaments for use in human bodies,animals and fishes or as preservatives of agricultural chemicals andfood.

When the compound of the present invention is used as a medicament forhuman bodies, its dosage may be within the range of generally from 50 mgto 1 g, preferably from 100 mg to 300 mg, per day per adult.

Its dosage as a drug for animals varies depending on the purpose of itsadministration (treatment or prevention), kind and size of each animalto be treated and kind and degree of each infected pathogenic bacterium,but the dosage may be within the range of generally from 1 mg to 200 mg,preferably from 5 mg to 100 mg, per 1 kg body weight per day.

The daily dose may be used once a day or by dividing it into 2 to 4doses per day. As occasion demands, the daily dose may exceed theaforementioned range.

Since the compound of the present invention has activity against a broadrange of microorganisms which cause various infectious diseases, it cantreat, prevent or alleviate diseases induced by these pathogens.

Illustrative examples of bacteria or bacterioid microorganisms on whichthe compound of the present invention is effective include those whichbelong to the genus Staphylococcus, Streptococcus pyogens, hemolyticstreptococcus, enterococcus, pneumococcus, those which belong to thegenus Peptostreptococcus, Neisseria gonorrhoeae, Escherichia coli, thosewhich belong to the genus Citrobacter, those which belong to the genusShigella, Klebsiella pneumoniae, those which belong to the genusEnterobacter, those which belong to the genus Serratia, those whichbelong to the genus Proteus, Pseudomonas aeruginosa, Haemophilusinfluenzae, those which belong to the genus Acinetobacter, those whichbelong to the genus Campylobacter, Chlamydia trachomatis and the like.

Illustrative examples of diseases which are induced by these pathogensinclude folliculitis, furuncle, carbuncle, erysipelas, phlegmon,lymphangitis, felon, subcutaneous abscess, hidradenitis, acneconglobata, infectious atheroma, perirectal abscess, mastitis,superficial secondary infections after injury, burn injury, operativewound and the like, pharyngitis, acute bronchitis, tonsilitis, chronicbronchitis, bronchiectasis, diffuse bronchiolitis, secondary infectionof chronic respiratory disease, pneumonia, pyelonephritis, cystitis,prostatitis, epididymitis, gonococcal urethritis, nonspecificurethritis, cholecystitis, cholangitis, bacillary dysentery, enteritis,uterine adnexitis, intrauterine infection, bartholinitis, blepharitis,hordeolum, dacryocystitis, tarsadenitis, corneal ulcer, octitis media,sinusitis, periodentitis, pericoronitis, jaw infection, peritonitis,endocarditis, sepsis, meningitis, skin infection and the like.

The compound of the present invention is also effective against variousmicroorganisms which cause infectious diseases in animals, such as thosewhich belong to the genera Escherichia, Salmonella, Pasteurella,Haemophilus, Bordetella, Staphylococcus, Mycoplasma and the like.

Illustrative examples of such diseases include colibacillosis, pullorumdisease, avian paratyphoid, avian cholera, infectious coryza,staphylococcosis, mycoplasma infection and the like in the case ofbirds; colibacillosis, salmonellosis, pasteurellosis, haemophilusinfection, atrophic rhinitis, exudative epidermis, mycoplasma infectionand the like in the case of pigs; colibacillosis, salmonellosis,hemorrhagic sepsis, mycoplasma infection, bovine pleuropneumonia, bovinemastitis and the like in the case of cattle; colisepsis, salmonellainfection, hemorrhagic sepsis, uterine empyema, cystitis and the like inthe case of dogs; and exudative pleurisy, cystitis, chronic rhinitis,haemophilus infection, kitten diarrhea, mycoplasma infection and thelike in the case of cats.

The antibacterial preparation which comprises the compound of thepresent invention can be prepared by selecting appropriate preparationdepending on each administration method and employing generally usedvarious preparation method. With regard to the dosage forms of theantibacterial preparation which uses the compound of the presentinvention as its principal agent, tablets, powders, granules, capsules,solutions, syrups, elixirs, oily or aqueous suspensions and the like canbe exemplified as oral preparations.

With regard to injections, a stabilizing agent, an antiseptic agent, asolubilizing agent and the like may be used in the preparation, and asolution which may contain these auxiliary agents may be contained in acontainer and made into a solid preparation by freeze-drying or the likemeans to be re-dissolved when used. In addition, a single dose may becontained in a single container or multiple doses may be contained inthe same container.

Also, solutions, suspensions, emulsions, ointments, gels, creams,lotions, sprays and the like can be exemplified as preparations forexternal use.

Solid preparations may contain pharmaceutically acceptable additivestogether with the active compound and can be prepared for example bymixing the compound with additives optionally selected from fillers,extenders, binders, disintegrators, solubilization enhancing agents,moistening agents, lubricating agents and the like.

As liquid preparations, solutions, suspensions, emulsions and the likecan be exemplified, which may contain a suspending agent, an emulsifyingagent and the like as additives.

Examples of the method for administering the compound of the presentinvention to animals include a method in which it is orally administereddirectly or by mixing it with feed, a method in which it is made into asolution and then orally administered directly or by mixing it withdrinking water or feed and a method in which it is administered byinjection.

With regard to the pharmaceutical preparations for use in theadministration of the compound of the present invention to animals, itcan be made optionally into powders, fine subtilaes, soluble powders,syrups, solutions or injections making use of the techniques generallyused in this field.

Formulation examples of the pharmaceutical preparations are shown below.

TABLE 1 Formulation Example 1 (Capsules): Compound of Inventive Example2 100.0 mg Corn starch 23.0 mg CMC calcium 22.5 mg Hydroxymethylcellulose 3.0 mg Magnesium stearate 1.5 mg Total 150.0 mg FormulationExample 2 (Solutions): Compound of Inventive Example 2 1-10 g Aceticacid or sodium hydroxide 0.5-2 g Ethyl para-hydroxybenzoate 0.1 gPurified water 87.9-98.4 g Total 100 g Formulation Example 3 (Powdersfor feed mixing use): Compound of Inventive Example 2 1-10 g Corn starch98.5-89.5 g Light anhydrous silicic acid 0.5 g Total 100 g

BEST MODE FOR CARRYING OUT INVENTION

Examples of the present invention are given below by way of illustrationand not by way of limitation. The antibacterial activity of eachcompound of interest was measured in accordance with the standard methodspecified by the Japan Society of Chemotherapy, with the results shownin Table 1 as MIC values (μg/ml).

REFERENCE EXAMPLE 14-(S)-Fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone

Method A

Diethylamino sulfur trifluoride (1.90 ml, 14.38 mmol) was added to amethylene chloride (50 ml) solution of4-(S)-hydroxymethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone (2.00 g, 9.12mmol) at −78° C., and the mixture was stirred overnight while graduallywarming to room temperature. The reaction solution was washed withsaturated sodium bicarbonate aqueous solution and saturated brine inthat order and then dried over anhydrous sodium sulfate. Afterevaporation of the solvent, the resulting residue was subjected to asilica gel chromatography to give 1.11 g (55%) of the title compoundfrom the 3% methanol-chloroform eluate in the form of a light yellowoil.

Method B

Triethylamine (6.36 ml, 45.63 mmol) was added to a methylene chloride(100 ml) solution of4-(S)-hydroxymethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone (5.00 g, 22.80mmol), methanesulfonyl chloride (2.65 ml, 34.24 mmol) was added dropwiseto the thus prepared solution which was cooled in an ice bath and thenthe resulting mixture was stirred for 30 minutes at the sametemperature. The reaction solution was washed with 10% citric acidaqueous solution and dried over sodium sulfate, and the solvent was thenevaporated. The thus obtained residue was dissolved in tetrahydrofuran(100 ml), mixed with 1N tetra-n-butylammonium fluoride-tetrahydrofuransolution (114 ml) and then heated under reflux for 1.5 hours. Thereaction solution was mixed with 10% citric acid aqueous solution,tetrahydrofuran was evaporated, the thus obtained residue was extractedwith chloroform (200 ml ×3) and then the resulting organic layers werecombined and dried over sodium sulfate. The solvent was evaporated andthe thus obtained residue was subjected to a silica gel chromatographyto give the title compound from the eluate of ethyl acetate:hexane=3:1,quantitatively in the form of a light yellow oil.

¹H-NMR (CDCl₃) δ: 1.52 (3H, d, J=7.33 Hz), 2.24-2.29 (1H, m), 2.52-2.63(2H, m), 3.10 (1H, t, J=9.76 Hz), 3.20 (1H, dd, J=5.37, 9.76 Hz),4.26-4.47 (2H, m), 5.50 (1H, q, J=7.32 Hz), 7.26-7.36 (5H, m).

REFERENCE EXAMPLE 24-(S)-Fluoromethyl-3-(R)-hydroxy-N-[1-(R)-phenylethyl]-2-pyrrolidone

In an atmosphere of nitrogen and at −78° C., 1.66 Nn-butyllithium-hexane solution (7.08 ml) was added dropwise to atetrahydrofuran (20 ml) solution of diisopropylamine (1.65 ml, 11.75mmol), and the mixture was stirred at 0° C. for 5 minutes. The reactionsolution was cooled to −78° C. and added dropwise to a tetrahydrofuran(20 ml) solution of4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone (2.00 g, 9.04mmol) at −78° C. in an atmosphere of nitrogen. After 15 minutes ofstirring at the same temperature, degassing was effected under a reducedpressure, the atmosphere in the reaction container was replaced withoxygen gas and then the reaction mixture was stirred at the sametemperature in an atmosphere of oxygen. After completion of thereaction, the reaction solution was mixed with 5% sodium thiosulfateaqueous solution, tetrahydrofuran was evaporated, the thus obtainedresidue was extracted with ethyl acetate (150 ml×3) and then theresulting organic layers were combined and dried over sodium sulfate.The solvent was evaporated and the thus obtained residue was subjectedto a silica gel chromatography to give 1.57 g (73%) of the titlecompound from the eluate of 3% methanol-chloroform in the form of whitecrystals.

¹H-NMR (CDCl₃) δ: 1.52 (3H, d, J=7.32 Hz), 2.31-2.48 (1H, m), 3.05-3.10(1H, m), 3.16-3.21 (1H, m), 4.29 (1H, d, J=9.37 Hz), 4.53-4.67 (2H, m),5.48 (1H, q, J=7.33 Hz), 7.26-7.37 (5H, m).

REFERENCE EXAMPLE 33-(S)-Azido-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone

Triethylamine (3.07 ml, 22.02 mmol) was added to a methylene chloride(40 ml) solution of4-(S)-fluoromethyl-3-(R)-hydroxy-N-[1-(R)-phenylethyl]-2-pyrrolidone(2.61 g, 11.00 mmol), methanesulfonyl chloride (1.28 ml, 16.54 mmol) wasadded dropwise to the thus prepared solution at −10° C. and then theresulting mixture was stirred for 30 minutes at the same temperature.The reaction solution was washed with 10% citric acid aqueous solutionand dried over sodium sulfate and then the solvent was evaporated. Thethus obtained residue was dissolved in N,N-dimethylformamide (80 ml),mixed with sodium azide (2.86 g, 44.00 mmol) and then stirred overnightat 100° C. The reaction solution was mixed with water, extracted withethyl acetate (200 ml×3) and then the resulting organic layers werecombined and dried over sodium sulfate, subsequently evaporating thesolvent. The thus obtained residue was subjected to a silica gelchromatography to give 1.81 g (63%) of the title compound from theeluate of ethyl acetate:hexane=1:3 in the form of a light yellow oil.

¹H-NMR (CDCl₃) δ: 1.56 (3H, d, J=7.32 Hz), 2.67-2.75 (1H, m), 3.02 (1H,dd, J=7.32, 10.25 Hz), 3.23 (1H, dd, J=4.39, 10.25 Hz), 4.27 (1H, d,J=8.30 Hz), 4.38 (1H, ddd, J=7.81, 9.28, 46.39 Hz), 4.59 (1H, ddd,J=5.86, 9.28, 46.37 Hz), 5.48 (1H, q, J=7.32 Hz), 7.26-7.37 (5H, m).

REFERENCE EXAMPLE 43-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone

Di-tert-butyl dicarbonate (3.01 g, 13.79 mmol) and 10% palladium oncarbon catalyst (1.80 g) were added to an ethanol (100 ml) solution of3-(S)-azido-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone (1.81g, 6.90 mmol), and the mixture was subjected to overnight catalytichydrogenation at room temperature. After removal of the catalyst byfiltration, the solvent of the resulting filtrate was evaporated, andthe thus obtained residue was subjected to a silica gel chromatography.From the eluate of ethyl acetate:hexane=1:2, 1.68 g (72%) of the titlecompound was obtained as white crystals.

¹H-NMR (CDCl₃) δ: 1.45 (9H, s), 1.53 (3H, d, J=7.32 Hz), 2.85-2.93 (1H,m), 3.06 (1H, dd, J=6.25, 10.74 Hz), 3.31 (1H, d, J=9.26 Hz), 4.32-4.53(3H, m), 5.08 (1H, brs), 5.49 (1H, q, J=6.83 Hz), 7.26-7.36 (5H, m).

REFERENCE EXAMPLE 53-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidine

While cooling in an ice bath, a 1 mol tetrahydrofuran solution (19.98ml) of borane-tetrahydrofuran complex was added dropwise to atetrahydrofuran (60 ml) solution of3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone(1.68 g, 4.99 mmol), and the resulting mixture was stirred overnight atroom temperature. The solvent was evaporated, and the thus obtainedresidue was mixed with an ethanol-water (4:1) mixed solvent (40 ml) andheated under reflux for 2 hours in the presence of triethylamine (8 ml).After spontaneous cooling, the solvent was evaporated. The thus obtainedresidue was mixed with chloroform and washed with saturated brine, theresulting organic layer was dried over sodium sulfate and then thesolvent was evaporated. The resulting residue was subjected to a silicagel chromatography to give 1.54 g (96%) of the title compound from theeluate of ethyl acetate:hexane=1:3 in the form of white crystals.

¹H-NMR (CDCl₃) δ: 1.35 (3H, d, J=6.84 Hz), 1.43 (9H, s), 2.38-2.78 (5H,m), 3.24 (1H, q, J=6.34 Hz), 4.37-4.57 (3H, m), 4.84 (1H, d, J=8.30 Hz),7.25-7.35 (5H, m).

REFERENCE EXAMPLE 63-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethylpyrrodine

10% Palladium on carbon catalyst (500 mg) was added to an ethanol (50ml) solution of3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]-pyrrolidine(484 mg, 1.50 mmol), and the mixture was subjected to overnightcatalytic dehydrogenation at 50° C. After removing the catalyst byfiltration, the solvent in the resulting filtrate was evaporated to givecrude product of the title compound quantitatively.

¹H-NMR (CDCl₃) δ: 1.44 (9H, s), 1.69 (1H, brs), 2.45-2.53 (1H, m), 2.66(1H, dd, J=5.37, 10.74 Hz), 2.90-2.95 (1H, m), 3.18 (2H, dd, J=7.81,10.74 Hz), 4.18-4.27 (1H, m), 4.44-4.53 (1H, m), 4.56-4.65 (1H, m).

INVENTIVE EXAMPLE 17-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-6-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

To a dimethyl sulfoxide (4 ml) solution of6,7-difluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid BF₂ complex (360 mg, 1.0 mmol) were added3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (218 mg,1.00 mmol) and triethylamine (400 μl), subsequently carrying out 1 dayof stirring at room temperature. Triethylamine was evaporated, theresulting residue was mixed with 10% citric acid aqueous solution andthen the thus precipitated material was collected by filtration andwashed with water. This was dissolved in 80% water-containing ethanol(50 ml), mixed with triethylamine (5 ml) and then heated overnight underreflux. The solvent was evaporated, and the thus obtained residue wasmixed with concentrated hydrochloric acid and stirred at roomtemperature for 15 minutes. The reaction solution was washed withchloroform and then, while cooling in an ice bath, alkalified with 50%sodium hydroxide aqueous solution. This was adjusted to pH 7.4 withconcentrated hydrochloric acid, and the aqueous layer was extracted withchloroform (300 ml×3). The organic layer was dried over sodium sulfate,the solvent was evaporated and then the resulting residue wasrecrystallized from 28% aqueous ammonia-ethanol to give 286 mg (70%) ofthe title compound in the form of light yellow crystals.

¹H-NMR (0.1N NaOD) δ: 1.41-1.62 (2H, m), 2.62-2.79 (1H, m), 3.44-3.47(1H, m), 3.57 (3H, s), 3.60-3.65 (1H, m), 3.70-3.73 (1H, m), 3.77-3.88(2H, m), 4.00-4.05 (1H, m), 4.55-5.08 (3H, m), 7.66 (1H, d, J=14.16 Hz),8.42 (1H, d, J=2.44 Hz).

Elemental analysis data for C₁₉H₂₀F₃N₃O₄.0.25H₂O: Calcd.: C, 54.87; H,4.97; N, 10.10 Found : C, 54.78; H, 4.83; N, 10.00 Melting point:232-238° C. (decomp.) Specific rotation: [α]_(D)=−13.22° (c=0.174, 0.1 Nsodium hydroxide solution)

INVENTIVE EXAMPLE 27-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

To a dimethyl sulfoxide (2 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3carboxylicacid EF₂ complex (345 mg, 1.00 mmol) were added3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (327 mg,1.00 mmol) and triethylamine (400 μl), subsequently carrying out 1 dayof stirring at room temperature. Triethylamine was evaporated, theresulting residue was mixed with 10% citric acid aqueous solution andthen the thus precipitated material was collected by filtration andwashed with water. This was dissolved in 80% water-containing ethanol(50 ml), mixed with triethylamine (5 ml) and then heated overnight underreflux. The solvent was evaporated, and the thus obtained residue wasmixed with concentrated hydrochloric acid and stirred at roomtemperature for 15 minutes. The reaction solution was washed withchloroform and then, while cooling in an ice bath, alkalified with 50%sodium hydroxide aqueous solution. This was adjusted to pH 7.4 withconcentrated hydrochloric acid, and the aqueous layer was extracted withchloroform (300 ml×3). The organic layer was dried over sodium sulfate,the solvent was evaporated, and the resulting residue was isolated andpurified by a preparative TLC through its development with a lower layerof chloroform:methanol:water=7:3:1 and then recrystallized from 28%aqueous ammonia-ethanol to give 185 mg (47%) of the title compound inthe form of light yellow crystals.

¹H-NMR (0.1N NaOD) δ: 0.90-1.20 (4H, m), 2.73-2.78 (1H, m), 3.41-3.44(1H, m), 3.58 (3H, s), 3.64-3.73 (3H, m), 3.90-3.96 (1H, m), 4.03-4.09(1H, m), 4.66-4.82 (1H, m), 7.65 (1H, d, J=14.65 Hz), 8.49 (1H, s).

Elemental analysis data for C₁₉H₂₁F₂N₃O₄.0.25H₂O: Calcd.: C, 57.35; H,5.45; N, 10.56 Found : C, 57.36; H, 5.46; N, 10.41 Melting point:204-207° C. (decomp.) Specific rotation: [α]_(D)=−92.00° (c=0.275, 0.1 Nsodium hydroxide solution)

REFERENCE EXAMPLE 73-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine

10% Palladium on carbon catalyst (640 mg) was added to an ethanol (15ml) solution of3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethyl-N-[1-(R)-phenylethyl]pyrrolidine(644 mg, 2.00 mmol), and the mixture was subjected to 2 hours ofcatalytic hydrogenation at 50° C. After removal of the catalyst byfiltration, the solvent in the resulting filtrate was evaporated, andthe thus obtained residue was mixed with 10% citric acid aqueoussolution and washed with dichloromethane (15 ml×3) and diethyl ether (15ml×1). The aqueous layer was adjusted to pH 10 to 11 with 1N sodiumhydroxide aqueous solution and then extracted with chloroform (50 ml×4).The organic layer was dried over sodium sulfate, the solvent wasevaporated and then the resulting residue was purified byrecrystallizing it from a chloroform-n-hexane mixed solvent to give 344mg (79%) of the title compound in the form of white crystals.

¹H-NMR (CDCl₃) δ: 1.45 (9H, s), 2.43-2.54 (1H, m), 2.67-2.70 (1H, m),2.92-3.00 (1H, m), 3.18-3.25 (2H, m), 4.28 (1H, br.s.), 4.49 (1H, ddd,J=23.93, 9.28, 4.40 Hz), 4.61 (1H, ddd, J=23.93, 9.77, 4.40 Hz), 4.89(1H, br.s.). IR (KBr disk) cm⁻¹: 3365, 3213, 2974, 2937, 2902, 2875,1682, 1525, 1458, 1444, 1392, 1369, 1336, 1300, 1288, 1281, 1248.Elemental analysis data for C₁₀H₁₉FN₂O₂.0.25H₂O: Calcd.: C, 53.92; H,8.82; N, 12.57 Found : C, 54.25; H, 8.74; N, 12.74 Melting point:78.0-79.3° C. Specific rotation: [α]_(D)=+28.60° (c=1.035, chloroform)

INVENTIVE EXAMPLE 37-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-6-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

To a dimethyl sulfoxide (4 ml) solution of6,7-difluoro-1-[2-(S)-fluoro-1-(R)cyclopropyl]-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (360 mg, 1.00 mmol) were added3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (218 mg,1.00 mmol) and triethylamine (400 μl), subsequently carrying out 1 dayof stirring at room temperature. The reaction solution was concentratedunder a reduced pressure, the thus concentrated solution was mixed with10% citric acid aqueous solution, and the thus precipitated material wascollected by filtration, washed with water, dissolved in a mixed solventof ethanol:water=4:1 (50 ml), mixed with triethylamine (5 ml) and thenheated overnight under reflux. The solvent was evaporated, and the thusobtained residue was mixed with concentrated hydrochloric acid andstirred at room temperature for 15 minutes. The reaction solution waswashed with chloroform and then, while cooling in an ice bath, theaqueous layer was alkalified with 50% sodium hydroxide aqueous solution.This was adjusted to pH 7.4 with concentrated hydrochloric acid and 1Nhydrochloric acid, and the aqueous layer was extracted with chloroform(300 ml×3). The organic layer was dried over sodium sulfate, the solventwas evaporated, and the resulting residue was recrystallized from 28%aqueous ammonia-ethanol to give 286 mg (70%) of the title compound inthe form of light yellow crystals.

¹H-NMR (0.1N NaOD) δ: 1.41-1.62 (2H, m), 2.62-2.79 (1H, m), 3.44-3.47(1H, m), 3.57 (3H, s), 3.60-3.65 (1H, m), 3.70-3.73 (1H, m), 3.77-3.88(2H, m), 4.00-4.05 (1H, m), 4.55-5.08 (3H, m), 7.66 (1H, d, J=14.16 Hz),8.42 (1H, d, J=2.44 Hz). Elemental analysis data forC₁₉H₂₀F₃N₃O₄.0.25H₂O: Calcd.: C, 54.87; H, 4.97; N, 10.10 Found : C,54.78; H, 4.83; N, 10.00 Melting point: 232-238° C. (decomp.) Specificrotation: [α]_(D)=−13.22° (c=0.174, 0.1 N sodium hydroxide solution)

INVENTIVE EXAMPLE 47-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3carboxylicacid

To a dimethyl sulfoxide (2 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (345 mg, 1.00 mmol) were added3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (327 mg,1.00 mmol) and triethylamine (400 μl), subsequently carrying out 1 dayof stirring at room temperature. The reaction solution was concentratedunder a reduced pressure, the thus concentrated solution was mixed with10% citric acid aqueous solution, and the thus precipitated material wascollected by filtration, washed with water, dissolved in a mixed solventof ethanol:water=4:1 (50 ml), mixed with triethylamine (5 ml) and thenheated overnight under reflux. The solvent was evaporated, and the thusobtained residue was mixed with concentrated hydrochloric acid andstirred at room temperature for 15 minutes. The thus treated residue waswashed with chloroform and then, while cooling in an ice bath, theaqueous layer was alkalified with 50% sodium hydroxide aqueous solution.This was adjusted to pH 7.4 with concentrated hydrochloric acid and 1Nhydrochloric acid, and the aqueous layer was extracted with chloroform(300 ml×3). The organic layer was dried over sodium sulfate, the solventwas evaporated, and the resulting residue was isolated and purified by apreparative TLC through its development with a lower layer ofchloroform:methanol:water=7:3:1 and then recrystallized from 28% aqueousammonia-ethanol to give 185 mg (47%) of the title compound in the formof light yellow crystals.

¹H-NMR (0.1N NaOD) δ: 0.90-1.20 (4H, m), 2.73-2.78 (1H, m), 3.41-3.44(1H, m), 3.58 (3H, s), 3.64-3.73 (3H, m), 3.90-3.96 (1H, m), 4.03-4.09(1H, m), 4.66-4.82 (1H, m), 7.65 (1H, d, J=14.65 Hz), 8.49 (1H, s).

Elemental analysis data for C₁₉H₂₁F₂N₃O₄.0.25H₂O: Calcd.: C, 57.35; H,5.45; N, 10.56 Found : C, 57.36; H, 5.46; N, 10.41 Melting point:204-207° C. (decomp.) Specific rotation: [α]_(D)=−92.00° (c=0.275, 0.1 Nsodium hydroxide solution)

COMPARATIVE EXAMPLE 17-[3-(R)-Amino-4-(R)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

To a dimethyl sulfoxide (2 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (507 mg, 1.48 mmol) were added3-(R)-tert-butoxycarbonylamino-4-(R)-fluoromethylpyrrolidine (419 mg,1.92 mmol) that has been synthesized in accordance with the proceduresdescribed in Reference Examples 1 to 6 using4-(R)-hydroxymethyl-N-[1-(R)-phenylethyl]-2-pyrrolidone which is adiastereomer of the starting material described in Reference Example 1,and triethylamine (454 μl), subsequently carrying out 38 hours ofstirring at room temperature. The reaction solution was concentratedunder a reduced pressure, the resulting residue was mixed with water (20ml) and then the thus precipitated crystals were collected by filtrationand washed with water. This was dissolved in a mixed solvent (30 ml) ofethanol:water=9:1, mixed with triethylamine (2 ml) and then heated underreflux for 4 hours. The solvent was evaporated, and the thus obtainedresidue was mixed with 10% citric acid aqueous solution (50 ml) andextracted with chloroform (100 ml×3). The organic layer was dried oversodium sulfate and the solvent was then evaporated. The thus obtainedresidue was dissolved in concentrated hydrochloric acid (10 ml) andwashed with dichloromethane (50 ml×3) and then, while cooling in an icebath, the aqueous layer was alkalified with 10 N sodium hydroxideaqueous solution. This aqueous layer was washed with dichloromethane (50ml×3), adjusted to pH 7.4 with concentrated hydrochloric acid and 1Nhydrochloric acid and then extracted with chloroform (100 ml×3). Theorganic layer was dried over sodium sulfate, the solvent was evaporated,and the resulting residue was purified by recrystallizing it from 28%aqueous ammonia-ethanol mixed solvent to give 472 mg (81%) of the titlecompound in the form of light yellow crystals.

¹H-NMR (0.1N NaOD) δ: 0.82—1.19 (4H, m), 2.65-2.75 (1H, m), 3.38 (1H, d,J=10.75 Hz), 3.51 (3H, s), 3.59-3.70 (3H, m), 3.84-3.88 (1H, m),4.00-4.06 (1H, m), 4.64-4.86 (2H, m), 7.61 (1H, d, J=14.65 Hz), 8.49(1H, s). IR (KBr disk) cm⁻¹: 3359, 3086, 2952, 2881, 1724, 1620, 1510,1446, 1436, 1373, 1352, 1327, 1315, 1267, 1219. Elemental analysis datafor C₁₉H₂₁F₂N₃O₄: Calcd.: C, 58.01; H, 5.38; N, 10.68 Found : C, 57.73;H, 5.40; N, 10.67 Melting point: 206.1-208.2° C. Specific rotation:[α]_(D)=+95.21° (c=1.065, 0.1 N NaOH solution)

INVENTIVE EXAMPLE 57-[3-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex

To a dimethyl sulfoxide (2 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (343 mg, 1.00 mmol) were added3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (284 mg,1.30 mmol) and triethylamine (307 μl), subsequently carrying out 21hours of stirring at room temperature. The reaction solution wasconcentrated under a reduced pressure, the thus concentrated solutionwas mixed with water (50 ml) and then the thus precipitated crystalswere washed with water and diethyl ether. These crystals were purifiedby recrystallizing them from ethanol to give 285 mg (53%) of the titlecompound in the form of light yellow crystals.

¹H-NMR (CDCl₃) δ: 1.14-1.21 (2H, m), 1.33-1.36 (2H, m), 1.47 (9H, s),2.78-2.84 (1H, m), 3.64 (4H, s), 3.87-3.90 (1H, m), 4.02-4.07 (1H, m),4.29-4.31 (1H, m), 4.55 (1H, br.s), 4.61-4.83 (2H, m), 5.00 (1H, br.s),7.84 (1H, d, J=13.67 Hz), 8.97 (1H, s). IR (KBr disk) cm⁻¹: 3423, 2981,1716, 1631, 1568, 1524, 1502, 1443, 1410, 1394, 1367, 1338, 1286, 1254.Elemental analysis data for C₂₄H₂₈BF₄N₃O₆.0.75H₂O: Calcd.: C, 51.96; H,5.36; N, 7.57 Found : C, 52.07; H, 5.27; N, 7.57 Melting point:154.3-155.2° C. (decomp.) Specific rotation: [α]_(D)=−1.03° (c=0.968,chloroform)

INVENTIVE EXAMPLE 67-[3-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

7-[3-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (244 mg, 440 μmol) was dissolved in a mixedsolvent (20 ml) of ethanol:water=4:1 and mixed with triethylamine (2ml), and the mixture was heated under reflux for 4 hours. The solventwas evaporated, and the resulting residue was mixed with 10% citric acidaqueous solution (50 ml) and extracted with chloroform (100 ml×3). Theorganic layer was dried over sodium sulfate and the solvent wasevaporated to give 256 mg of crude product of the title compound whichwas then purified by its recrystallization from a chloroform-n-hexanemixed solvent to give 194 mg (87%) of the title compound in the form oflight yellow crystals.

¹H-NMR (0.1N NaOD) δ: 0.68-1.05 (4H, m), 1.30 (9H, s), 2.70-2.80 (1H,m), 3.34 (1H, d, J=10.26 Hz), 3.44 (3H, s), 3.52 (1H, t, J=8.30 Hz),3.62 (1H, t, J=8.30 Hz), 3.83-3.85 (1H, m), 3.90-3.95 (1H, m), 4.27 (1H,br.s), 4.43-4.62 (2H, m), 7.51 (1H, d, J=14.16 Hz), 8.34 (1H, s). IR(KBr disk) cm⁻¹: 3359, 3086, 2976, 2935, 2881, 1716, 1624, 1512, 1450,1392, 1369, 1313, 1273, 1248. Elemental analysis data forC₂₄H₂₉F₂N₃O₆.0.5H₂O: Calcd.: C, 57.36; H, 6.02; N, 8.36 Found : C,57.40; H, 5.97; N, 8.21 Melting point: 111.0-113.7° C. Specificrotation: [α]_(D)=−21.17° (c=0.992, chloroform)

INVENTIVE EXAMPLE 77-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

Concentrated hydrochloric acid (2 ml) was added to7-[3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylic acid (140 mg, 0.28 mmol) which was cooled in an ice bath,and the mixture was stirred for 30 minutes at the same temperature. Thereaction solution was diluted with water (50 ml) and washed withchloroform (50 ml×3) and then, while cooling in an ice bath, the aqueouslayer was alkalified with 50% sodium hydroxide aqueous solution. Theaqueous layer was washed with dichloromethane (50 ml×3), adjusted to pH7.4 with concentrated hydrochloric acid and 1N hydrochloric acid andthen extracted with chloroform (100 ml×3). The organic layer was driedover sodium sulfate, the solvent was evaporated, and the thus obtainedresidue was purified by its recrystallization from a 28% aqueousammonia-ethanol mixed solvent to give 94 mg (85%) of the title compoundin the form of light yellow crystals.

¹H-NMR (0.1N NaOD) δ: 0.79-1.12 (4H, m), 2.65-2.71 (1H, m), 3.35 (1H, d,J=10.74 Hz), 3.49 (3H, s), 3.60-3.67 (3H, m), 3.83-3.88 (1H, m),3.98-4.02 (1H, m), 4.58-4.79 (2H, m), 7.58 (1H, d, J=14.64 Hz), 8.42(1H, s). IR (KBr disk) cm⁻¹: 3452, 3072, 2952, 2881, 1726, 1622, 1512,1446, 1439, 1369, 1352, 1315, 1267. Melting point: 203.2-205.1° C.(decomp.) Elemental analysis data for C₁₉H₂₁F₂N₃O₄.0.25H₂O: Calcd.: C,57.35; H, 5.37; N, 10.56 Found : C, 57.56; H, 5.37; N, 10.59 Specificrotation: [α]_(D)=−90.45° (c=0.995, 0.1 N NaOH solution)

INVENTIVE EXAMPLE 8

7-[3-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid diacetoxyborane complex

To an acetonitrile (3 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid diacetoxyborane complex (423 mg, 1.00 mmol) were added3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (327 mg,1.50 mmol) and triethylamine (280 μl), subsequently carrying out 15hours of stirring at room temperature. The reaction solution wasconcentrated under a reduced pressure, and the thus concentratedsolution was mixed with chloroform (50 ml) and washed with 10% citricacid aqueous solution and saturated brine in that order. The organiclayer was dried over sodium sulfate, the solvent was evaporated, and thethus obtained residue was subjected to a silica gel columnchromatography. The crystals obtained from the eluate ofchloroform:methanol=97:3 were purified by their recrystallization from achloroform-n-hexane mixed solvent to give 599 mg (93%) of the titlecompound in the form of yellow crystals.

¹H-NMR (CDCl₃) δ: 1.11-1.18 (2H, m), 1.26-1.31 (2H, m), 1.47 (9H, s),2.05 (6H, s), 2.75-2.83 (1H, m), 3.57 (3H, s), 3.57-3.64 (1H, m),3.78-3.83 (1H, m), 3.94-4.06 (2H, m), 4.15-4.20 (1H, m), 4.53-4.88 (4H,m), 7.89 (1H, d, J=13.18 Hz), 9.06 (1H, s). IR (KBr disk) cm⁻¹: 3318,2973, 1716, 1631, 1571, 1529, 1446, 1369, 1338, 1274, 1249. Elementalanalysis data for C₂₈H₃₂BF₂N₃O₁₀.0.5H₂O: Calcd.: C, 52.58; H, 5.44; N,6.57 Found : C, 52.51; H, 5.75; N, 6.28 Melting point: 142.4-144.2° C.(decomp.) Specific rotation: [α]_(D)=−8.04° (c=1.032, chloroform)

INVENTIVE EXAMPLE 97-[3-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

7-[3-(S)-tert-Butoxycarbonylamino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid diacetoxyborane complex (435 mg, 0.70 mmol) was suspended in amixed solution (10 ml) of ethanol:water=4:1 and mixed with triethylamine(2 ml), and the suspension was heated under reflux for 10 hours. Thereaction solution was concentrated under a reduced pressure, and theresulting residue was mixed with chloroform (50 ml) and washed with 10%citric acid aqueous solution and water. The organic layer was dried oversodium sulfate, the solvent was evaporated, and the resulting residuewas purified by its recrystallization from an ethanol-n-hexane mixedsolvent to give 272 mg (79%) of the title compound in the form of lightyellow crystals.

Its data of various instrumental analyses such as ¹H-NMR and the likecoincided with the data described in

INVENTIVE EXAMPLE 6 REFERENCE EXAMPLE 83-(S)-Amino-4-(S)-fluoromethylpyrrolidine dihydrochloride

Concentrated hydrochloric acid (1 ml) was added to3-(S)-tert-butoxycarbonylamino-4-(S)-fluoromethylpyrrolidine (441 mg,2.02 mmol) which was cooled in an ice bath, and the mixture was stirredfor 10 minutes. The reaction solution was mixed with water (5 ml) andwashed with dichloromethane (5 ml×3) and diethyl ether (5 ml×1). Theaqueous layer was concentrated under a reduced pressure, and theresulting residue was purified by its recrystallization from methanol togive 288 mg (75%) of the title compound in the form of white crystals.

¹H-NMR (D₂O) δ: 3.07 (1H, br.d, J=33.69 Hz), 3.51-3.61 (2H, m), 3.74(1H, dd, J=12.69, 7.81 Hz), 3.90 (1H, dd, J=13.18, 7.81 Hz), 4.33 (1H,dd, J=13.18, 7.32 Hz), 4.75-4.99 (2H, m). IR (KBr disk) cm⁻¹: 2910,2594, 2445, 1610, 1581, 1558, 1504, 1450, 1411, 1394, 1375, 1358, 1329,1308, 1292, 1267, 1242, 1209. Elemental analysis data for C₅H₁₁FN₂.2HCl:Calcd.: C, 31.43; H, 6.83; N, 14.66 Found : C, 31.29; H, 6.87; N, 14.58Melting point: 198.1-199.0° C. Specific rotation: [α]_(D)=−2.81°(c=1.033, H₂O)

INVENTIVE EXAMPLE 10

7-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex

To a dimethyl sulfoxide (2 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (343 mg, 1.00 mmol) were added3-(S)-amino-4-(S)-fluoromethylpyrrolidine dihydrochloride (268 mg, 1.40mmol) and triethylamine (585 μl), subsequently carrying out 15 hours ofstirring at room temperature. The reaction solution was concentratedunder a reduced pressure, the thus concentrated solution was mixed withwater (100 ml), washed with chloroform (50 ml×3) and then adjusted to pH6.9 by adding saturated sodium bicarbonate aqueous solution, and theaqueous layer was extracted with chloroform (100 ml×4). The organiclayer was dried over sodium sulfate, the solvent was evaporated, and theresulting residue was purified by its recrystallization from ethanol togive 412 mg (92%) of the title compound in the form of light yellowcrystals.

¹H-NMR (CDCl₃) δ: 1.03-1.43 (4H, m), 2.65-2.71 (1H, m), 3.49-3.53 (1H,m), 3.64 (3H, s), 3.72-3.76 (1H, m), 3.77-3.79 (1H, m), 4.05-4.10 (1H,m), 4.26-4.30 (1H, m), 4.76 (2H, br.d, J=46.64 Hz), 7.88 (1H, d, J=13.68Hz), 8.97 (1H, s). IR (KBr disk) cm⁻¹: 3064, 2944, 2889, 1722, 1633,1566, 1520, 1504, 1444, 1402, 1363, 1329, 1290, 1250, 1220. Elementalanalysis data for C₁₉H₂₀BF₄N₃O₄.0.25H₂O: Calcd.: C, 51.20; H, 4.64; N,9.43 Found : C, 51.00; H, 4.54; N, 9.35 Melting point: 214.1-214.7° C.(decomp.) Specific rotation: [α]_(D)=−125.800 (c=0.996,N,N-dimethylformamide)

INVENTIVE EXAMPLE 11

7-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

7-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid difluoroborane complex (348 mg, 781 μmol) was dissolved in a mixedsolution (20 ml) of ethanol:water=4:1 and mixed with triethylamine (2ml), and the mixture was heated under reflux for 4 hours. The solventwas evaporated, and the resulting residue was dissolved by addingconcentrated hydrochloric acid and 1N hydrochloric acid, washed withchloroform (50 ml×3) and then, while cooling in an ice bath, alkalifiedwith 50% sodium hydroxide aqueous solution. The aqueous layer was washedwith dichloromethane (50 ml×3), adjusted to pH 7.4 with concentratedhydrochloric acid and 1N hydrochloric acid and then extracted withchloroform (100 ml×3). The organic layer was dried over sodium sulfate,the solvent was evaporated, and then the resulting residue was purifiedby its recrystallization from a 28% aqueous ammonia-ethanol mixedsolvent to give 205 mg (67%) of the title compound in the form of lightyellow crystals.

Its data of various instrumental analyses such as ¹H-NMR and the likecoincided with the data described in

INVENTIVE EXAMPLE 7 INVENTIVE EXAMPLE 12

7-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid diacetoxyborane complex

To an acetonitrile (3 ml) solution of1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid diacetoxyborane complex (423 mg, 1.00 mmol) were added3-(S)-amino-4-(S)-fluoromethylpyrrolidine dihydrochloride (287 mg, 1.50mmol) and triethylamine (700 μl), subsequently carrying out 15 hours ofstirring at room temperature. The reaction solution was concentratedunder a reduced pressure, and the thus obtained residue was mixed withchloroform (50 ml), washed with water and then dried over sodiumsulfate. The solvent was evaporated, the resulting residue was subjectedto a silica gel column chromatography and then the crystals thusobtained from the eluate of chloroform:methanol=10:1 were washed withether to give 459 mg (88%) of the title compound in the form of lightyellow crystals.

¹H-NMR (CDCl₃) δ: 1.03-1.41 (4H, m), 2.05 (6H, s), 2.64-2.70 (1H, m),3.43-3.47 (1H, m), 3.57 (3H, s), 3.68-3.72 (1H, m), 3.83-3.89 (2H, m),4.02-4.07 (1H, m), 4.17-4.20 (1H, m), 4.67-4.70 (1H, m), 4.79-4.82 (1H,m), 7.87 (1H, d, J=13.19 Hz), 9.04 (1H, s). IR (KBr disk) cm⁻¹: 3378,2931, 2884, 1716, 1627, 1573, 1527, 1446, 1373, 1338, 1280, 1243, 1218.Elemental analysis data for C₂₃H₂₆BF₂N₃O₈.0.5H₂O: Calcd.: C, 52.09; H,5.13; N, 7.92 Found : C, 52.11; H, 5.36; N, 7.80 Melting point:182.4-185.6° C. (decomp.) Specific rotation: [α]_(D)=−80.02° (c=1.001,chloroform)

INVENTIVE EXAMPLE 137-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid

7-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid diacetoxyborane complex (365 mg, 0.70 mmol) was suspended in amixed solution (10 ml) of ethanol:water=4:1 and mixed with triethylamine(2 ml), and the mixture was heated under reflux for 14 hours. Thereaction solution was concentrated under a reduced pressure, and thethus obtained residue was dissolved by adding concentrated hydrochloricacid and 1 N hydrochloric acid and washed with chloroform (50 ml×3) andthen, while cooling in an ice bath, the aqueous layer was alkalifiedwith 50% sodium hydroxide aqueous solution. The aqueous layer was washedwith dichloromethane (50 ml×3), adjusted to pH 7.4 with concentratedhydrochloric acid and 1N hydrochloric acid and then extracted withchloroform (100 ml×3). The organic layer was dried over sodium sulfate,the solvent was evaporated, and then the resulting residue was purifiedby its recrystallization from a 28% aqueous ammonia-ethanol mixedsolvent to give 218 mg (81%) of the title compound in the form of lightyellow crystals.

Its data of various instrumental analyses such as ¹H-NMR and the likecoincided with the data described in Inventive Example 7.

TABLE 1 Antibacterial activity (minimum inhibitory concentration, μg/ml)Compounds Strains Ex. 1 Ex. 2 Comp. Ex. 1 E. coli, NIHJ ≦0.003 ≦0.003≦0.003 S. flexneli, 2A 5503 0.006 0.006 0.013 Pr. vulgaris, 08601 0.0130.013 0.013 Pr. mirabilis, IFO- 3849 0.025 0.05 0.10 Ser. marcescens,10100 0.05 0.05 0.10 Ps. aeruginosa, 32104 0.20 0.20 0.20 Ps.aeruginosa, 32121 0.05 0.10 0.10 X. maltophilia, IID 1275 0.20 0.10 0.20S. aureus, 209P 0.013 0.013 0.025 S. epidermidis, 56500 0.05 0.05 0.10Str. pyogenes, G-36 0.10 0.10 0.20 Str. faecalis, ATCC- 0.10 0.10 0.2019433 S. aureus, 870307 0.20 0.39 0.78

Industrial Applicability

Thus, as has been described in the foregoing, the compound of thepresent invention is possessed of excellent antibacterial activity andsafety, so that it is useful as medicaments.

What is claimed is:
 1. A compound represented by the following formula(I), a salt thereof, or a hydrate thereof:

wherein R¹ represents a hydrogen atom or an alkyl group having 1 to 6carbon atoms, wherein said alkyl group may have one or more substituentsselected from the group consisting of a hydroxyl group, a halogen atom,an alkylthio group having 1 to 6 carbon atoms and an alkoxyl grouphaving 1 to 6 carbon atoms, R² represents a halogenomethoxyl group or analkoxyl group having 1 to 6 carbon atoms, R³ represents an alkyl grouphaving 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms,a halogenoalkyl group having 1 to 6 carbon atoms, a cyclic alkyl grouphaving 3 to 6 carbon atoms which may have a substituent, a heteroarylgroup which may have a substituent, an alkoxyl group having 1 to 6carbon atoms or an alkylamino group having 1 to 6 carbon atoms, and R⁴represents a hydrogen atom, a phenyl group, an acetoxymethyl group, apivaloyloxymethyl group, an ethoxycarbonyl group, a choline group, adimethylaminoethyl group, a 5-indanyl group, a phthalidinyl group, a5-alkyl-2-oxo-1,3-dioxol-4-ylmethyl group, a 3-acetoxy-2-oxobutyl group,an alkyl group having 1 to 6 carbon atoms, an alkoxylmethyl group having2 to 7 carbon atoms or a phenylalkyl group composed of an alkylene grouphaving 1 to 6 carbon atoms and a phenyl group.
 2. The compound, the saltthereof, or the hydrate thereof according to claim 1, wherein R¹ in theformula (I) is a hydrogen atom.
 3. The compound, the salt thereof, orthe hydrate thereof according to claim 1, wherein R² in the formula (I)is a methoxyl group.
 4. The compound, the salt thereof, or the hydratethereof according to claim 1, wherein R³ in the formula (I) is acyclopropyl group.
 5. The compound, the salt thereof, or the hydratethereof according to claim 1, wherein R³ in the formula (I) is ahalogenocyclopropyl group.
 6. The compound, the salt thereof, or thehydrate thereof according to claim 1, wherein R³ in the formula (I) is a1,2-cis-halogenocyclopropyl group.
 7. The compound, the salt thereof, orthe hydrate thereof according to claim 1, wherein R³ in the formula (I)is a stereochemically pure substituent.
 8. The compound, the saltthereof, or the hydrate thereof according to claim 1, wherein R³ in theformula (I) is a (1R,2S)-2-halogenocyclopropyl group.
 9. The compound,the salt thereof, or the hydrate thereof according to claim 1, whereinR³ in the formula (I) is a (1R,2S)-2-fluorocyclopropyl group.
 10. Thecompound, the salt thereof, or the hydrate thereof according to claim 1,wherein the compound of formula (I) is a stereochemically pure compound.11. An antibacterial agent which comprises a compound described in anyone of claims 1 to 10 or 22-23, a hydrate thereof, a salt thereof or ahydrate of the salt thereof, as an active ingredient. 12.7-[3-(S)-Amino-4-(S)-fluoromethyl-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid, a salt thereof, or a hydrate thereof. 13.7-[3-(S)-Amino4-(S)-fluoromethyl-1-pyrrolidinyl]-6fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylicacid, a salt thereof, or a hydrate thereof.